development_tools: make gcc_version public api

Library/Homebrew/development_tools.rb

@@ -114,9 +114,9 @@ class DevelopmentTools
 
     # Get the GCC version.
     #
-    # @api internal
+    # @api public
     sig { params(cc: String).returns(Version) }
-    def gcc_version(cc)
+    def gcc_version(cc = host_gcc_path.to_s)
       (@gcc_version ||= T.let({}, T.nilable(T::Hash[String, Version]))).fetch(cc) do
         path = HOMEBREW_PREFIX/"opt/#{CompilerSelector.preferred_gcc}/bin"/cc
         path = locate(cc) unless path.exist?